Studies On The Synthesis, Characterization And Application Of Bisacylthioureas

Using triphosgene (BTC) and diacid as raw material, methylbenzene as solvent, and N,N-dimethylformamide (DMF) as a catalyst, succinyl chloride and adipoyl dichloride were synthesized, and the better technology conditions were found. The yields of succinyl chloride and adipoyl dichloride respectively reached84.8%and97.0%when the ratio of diacid, BTC to DMF was1:1.5:0.02(based on0.04mol diacid) at60℃in20mL methylbenzene for3.5hours.Nine bisacylthioureas which have symmetric structure were synthesized by phase transfer catalyst technologies with dichloride, KSCN and organic amine as raw material and PEG-400as a catalyst. The optimum reaction conditions of succinyl bisthiourea are as follows: n(succinyl chloride):n(KSCN):n(PEG-400):n(primary amine)=1.0:2.5:0.075:2.5, dichloromethane was60mL, substitution reaction time and addition reaction time were2hours at25℃. The yields of N,N’-di-n-propyl-N",N’"-(1,4-succinyl) bisthiourea and N,N’-di-n-propyl-N",N’"-(1,4-succinyl) bisthiourea respectively reached58.0%and56.2%.When the ratio of adipoyl chloride, KSCN, PEG-400to secondary amine was1.0:2.5:0.08:2.1at25℃in60mL dichloromethane for substitution reaction2hours and addition reaction1.5hours, the yields of N,N’-tetraalkyl-N",N’"-(1,6-adipoyl)bisthiourea was between70.1%and73.6%. Extending substitution reaction time to4.5hours, terephthaloyl bisthiourea was synthetized under the same conditions by reactions of terephthalyl chloride and3-alkoxy propyl amine, the yields of N,N’-di(3-alkoxy-propyl)-N",N’"-terephthaloyl bisthiourea from71.7%to80.1%. The structures of compounds have been confirmed by UV, IR, elemental analysis and1HNMR.Based on the experiment, the changes of pH value, the analysis of UV and IR spectra, the interactions between bisacylthiourea and metal ions are systemically studied. The bisacylthiourea can chemically react with Cu2+or Ag+ions in the aqueous solution, but can not chemically react with Fe2+、Fe3+、Co2+、Ni2+、Zn2+or Pb2+.That fully explained that bisacylthiourea has favourable selective ability to Cu2+or Ag+ions.The results of adsorption experiments showed the adsorption capacity of N,N’-tetraethyl-N",N’"-(1,6-adipoyl)bisthiourea onto chalcopyrite surface larger than adsorption capacity onto pyrite, sphalerite and galena surface.